Apparatus for dehydrating petroleum emulsions



F. W. HARRRS.

APPARATUS FOR DEHYDRATING PETROLEUM EMULSIONS.

APPLICATION FILED AUG-8.1918- RENEWED MAY 31, I921- Patented Jan. 31, 1922.

UNITED STATES PATENT OFFICE.

FORD W. HARRIS, OF LOS ANGELES, CALIFORNIA, AS SIG-NOR, BY MESNE ASSIGN- MENTS, TO- PETROLEUM RECTIFYING COMPANY, OF SAN FRANCISCO, CALI- FORNIA, A CORPORATION OF CALIFORNIA.

APPARATUS FOR D EHYDRATINQ PETROLEUM EMULSIONS.

Specification of Letters Patent. Patented J an, 31 1922 Application filed August 8, 1918, Serial No. 249,021. Renewed May 31, 1921. Serial No. 473,769.

710 all whom it may concem:

Be it known that I, Form W. HARRIs, a

' citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California have invented a new and useful Apparatus for Dehydrating Petroleum Emulsions, of which the follow-' in is a specification.

lwy'invention relates to the art of dehydrating petroleum emulsions. There are found in nature large quantities of petroleum emulsions in which the Water content is in the form of infinitely small drops which will not settle out under the action of gravity even if allowed to stand for long periods. It is a well known fact .that if these emulsions are subjected to the action of an electric current, or in other words, if an electric current is caused to pass through such emulsions, that the drops for some reason which is not fully understood, tend to increase in size by the agglomeration of these minute particles. If these larger drops are again subjected to the action of an electric current they are still further agglomerated,'and this action continues until such a time as the drops are large enough to be settled out by gravity. I have found that this agglomerating action is due to the initial passage of the current across any path and that a continuance of the current after the initial rush is both unnecessary and inefiicient. In other words, it has seemed to be the puncturing of the oil film between the water globules which causes the agglomeration.

I have found that where an electric fieldency for the dehydrating action to concentrate in small areas to the exclusion of the remainder of the body of emulsion. This I believe is due to, the fact that once the agglomeration is started and the large drops are formed that the resistance along the paths formed of the larger globules is very much less than the resistance along a path formed through the emulsified particles of water so that these paths through the heavy particles take practically all the energy.

I have, therefore, found it necessary to provide in addition to the {electrical field some means by which this localized action may be prevented. This I have succeeded in accomplishing by a processwhich is carried on by the apparatus illustrated in the annexed drawing, in which Fig. 1 is a side elevation, partly in section, of a dehydrator involving my invention, and Fig. 2 is a section on the line 2-2 of Fig. 1, viewed in the direction of the arrows.

This dehydrator consists of a vertical pipe 11 which forms the outer electrode and which is connected at the bottom into the pressure side of a pump 12 which is supplied with emulsion through a pipe 13. The pipe 11 is connected into the bottom of an enclosed chamber 14, being attached to the bottom thereof by means of a flange 15-into which the pipe 11 is threaded. Located in-' side the chamber 14 is a-similar flange 16 into which a pipe 17 which forms a continuation of the pipe 11, is, threaded.

Secured in the top of the closed chamber 14 and projecting downwardly therein is an insulator 18 which may be of porcelain or which may be built up out of other insulating material. An outlet pipe 19 connects with the side of the chamber 14. Projecting downwardly through the insulator 18 is an inner electrode support 20, this support passing through a stuffing box 21 provided with a gland 22. The gland 22 1s threaded in the stuffing box 21, and packing 23 is compressed thereby so that the support 20 is frictionally held therein." 1

The electrode support 20 has-secured to the lower end thereof a chain 30 which forms the inner-electrode. This chainis secured at its lower. end to an insulator-31 towhich is also secured a weight 32 which is formed of radial members 33 connected to a'common hub 34 as shown inFig. 2. A transformer 35 has its primary 36 connected to any suitable source of electrical energy, the secondary terminals 37 and 38.0f the transformer 35 being connected to the insulator support 20 and the chamber 14 so that an electric potential is impressed between the chain 30 which forms the inner electrode and the pipes 11 and 17 which form the outer electrode. The'exact regulation of the speed of the emulsion-through the pipe 11 being I essential, it is necessary that the speed of the 4 41 for the purpose of regulating the speed pump 12 be adjustable if different kinds of emulsion are to be treated, and 1t is necessary to initially adjust this speed even where the apparatus is run continuously on a given kind of oil;

In the drawings show a steam pump 12 which is fedwith steam through a pipe 40,

the flow of steam being control ed by a valve of the pump. Where/motor driven pumps are used other. speed control devlces are necessary or the proper speed may be first ascertained by suitable regulation after which further regulation is unnecessary. An

ammeter 42- allows the amount of current taken to be ascertained at any time and a starting rheostat 43 is inserted in the pr1-- mary circuit of the transformer so that the current which will flow therethrough when connected to constant potential mains may be limited.

The method of operation of my invention is asfollows: I

The emulsion to be treated is drawn up wardly through the pipes 11 and 17, which,

infefiect, form the'out'er electrode, thisemulsion surrounding the h inner electrode 20. The inner electrode 20 may be moved up and down so that varying amounts thereof project into the pipe 11, or links may be removed or added to the chain 30 for the same purpose. In its passage through the space between the cylindrical inner surface of the pipe 11 and the outer surface of the inner electrode;30, the emulsion is subjected to electrical stresses, the current flowing in an infinite number of vsmall paths throughthe emulsion, jumping from water drop to water drop and puncturing films of oil therebetween. r

If theoilis moved slowly there is likely to. be a concentration of electric currerit in one or more spots, this concentration rapidly building up larger masses of "water through which the current shoots continuously.-

These larger masses of water are of rela gressive from the bottom ,to the top of the pipe 11, in other words,{ with a very fine emulslon entering the bott m of the pipe 11, the current first flows th ough paths; made up entirely of emulsion. The size of the water drops increases as the liquid flows upwardly, and at the top of the pipe 11 these drops are sufliciently large to readily settle if run into a separate settling space. There is an economical size to which it pays tov agglomerate the water, in other words, there. is

that action is continued too long the amountv of current which is taken will be excessive.

For this reason it is necessary to regulate the area of electric surface which can con- 1 veniently be done by moving the inner electrode 20 up and down inside the pipe 11 or by changing its length by taking out or adding links to the chain until the proper de ree of agglomeration is secured.

.Tn practice a certain length of chain 30 is chosen. For example working on 16 gravity Baum oil I have found that the pipes 11 and 17 may well be six inches inside diameter and that the chain 30 may be about six feet long so that the distance be tween electrodes is something less than three inches and the length of the field is about six feet. The emulsion, which is preferably heated to about 150 degrees F., is then pumped upwardly through the pipe 11. If this emulsion is pumped slowly the ammeter 42 will indicate an excessive current which can be limited by the starting rheostat {13. In practice I prefer to use a transformer 35 having a primary voltage of 220 volts, so that its primary can be connected directly to constant potential lighting circuit, and a secondary voltage. of 15,000 volts which is impressed on the emulsion. Under such conditions I pump. the emulsion at such a speed that the ammeter 42 indicates about ten ampe-res with the rheostat 43 so adjusted thatthe resistors therein are entirely out of eircuit. There willbe an occasional sharp snap heard and the ammeter needle may momentarily swing over as heavy momentary currents pass'but in general when once started thev apparatus operates without noise, other than a slight buzzing sound due to the vconstant forming and breakingv of the current paths. This is possible only when the rate of flow of the emulsion is such that only unstable paths are formed,

the term unstable paths being used to des ignate paths formed of water globules,

whose average cross section and whose.

length is such that they willnot persist in the mass of moving emulsion.

The pipe 17 is necemary. to prevent the Lwaterwhich settles in the bottom of the chamber 14.- from flowing back into the pipe 11. By running this pipe up close tothe bottom of the insulator 18 the liquid to be treated is 'in constant motion through the electric field, and after having passed through the electric field, it passes downwardly sothat any tendency for water to settle is taken care of by the fact that the pipe 19 is below the end of the pipe 17 therefore drawing off the Water With the cleaned oil. The cleaned oil with the free water contained therein is run into a separate settling tank in which the water. and oil are allowed to separate by gravity.

I claim as my invention:

1. In a dehydrator for petroleum emulsions a vertically disposed inlet pipe electrically connected to form one electrode, a flexible electrode of chain or the like suspended Within said pipe and insulated therefrom means for receiving the emulsion at the bottom of said pipe and a receiving chambe surrounding the upper end of said pipe for said emulsion after its passage through said pipeand outlet meansfro-m said chamber for the constituents of the emulsion after treatment.

2. Dehydrating apparatus as set forth in claim 1 and means for retaining the suspended electrode in tension.

3. Dehydrating apparatus as set forth in claim 2 wherein the last named means is provided with spacing members to retain the end of the suspended electrode central within the said pipe.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 2nd day of August, 1918.

FORD W. HARRIS. 

